1. Field of the Invention
The present invention relates to a liquid crystal display, and in particular, to an optically compensated bend mode liquid crystal display.
2. Description of the Related Art
Liquid crystal displays (LCDs) are one type of flat panel displays that are now widely used. The LCD includes two display panels in which field generating electrodes such as pixel electrodes and a common electrode are formed, respectively, and a liquid crystal (LC) layer interposed between the display panels. A voltage applied to the pixel electrodes and the common electrode generates an electric field in the LC layer which determines the orientation of the LC molecules and controls the polarization of incident light to display images.
Various methods have been proposed to improve the response speed and the reference viewing angle of the LCD. An example thereof is an optically compensated bend (OCB) mode LCD.
In the OCB mode LCD, the applied electric field changes the alignment of LC molecules from a horizontal arrangement to a vertical arrangement until the LC molecules reach from the display panel surfaces to the center of an area between the display panels. In the OCB mode display, the LC molecules are symmetrically arranged from the two display panels to the center of the area.
However, the OCB mode LCD is unstable compared with LCDs of another mode and, when a voltage is not applied, the LC molecules have a splay alignment. It would be of great advantage if the alignment of the LC molecules could be changed from the splay alignment to a bend alignment for more effective displaying of images.